There is no need for both.

windows is meant:

For questions not specific to a single version of Microsoft Windows. Otherwise, use a more specific tag such as windows-7 or windows-10.

Having said that, I would not normally have removed it when adding a version specific tag like windows-10 as it does not cause any harm, and allows someone to easily find all questions about Windows using a tag search.

The exception to that would be a case where there were already 5 tags (5 is the maximum number of allowed tags). Then I would remove windows to leave space for windows-10.

I probably wouldn't have made an edit that only added windows back in to the question.

There is no need for both.

The windows tag is meant:

For questions not specific to a single version of Microsoft Windows. Otherwise, use a more specific tag such as windows-7 or windows-10.

Having said that, I would not normally have removed it when adding a version specific tag like windows-10 as it does not cause any harm and allows someone to easily find all questions about Windows using a tag search.

The exception to that would be a case where there were already 5 tags (5 is the maximum number of allowed tags). Then I would remove windows to leave space for windows-10.

I probably wouldn't have made an edit that only added windows back in to the question.